Carburetor



March 31, 1931. H, may 11,798,162

CARBURETOR Filed Dec. 12, 1927 2 Sheets-Sheet l I (Z w h N I a EVEEIEIE March 31, 1931. Q KlRBY 1,79M62 CARBURETOR Filed Dec. 12, 1927 2 sheets-Shem 2 Patented Mar 31, 193i GEABLES E. KIREY, 0F FLINT, MICHIGAN, ASSIGNOR T0 MARVEL C UTER COM- PANY, A CORPORATION OF ILLINOIS CALRYBURETOB Application filed December 12, 1927. Serial No. 239,376.

This invention relates to carburetors for internal combustion engines and has special reference to a carburetor embodying a weighted air valve which also acts as an air pump to injectadditional fuel on a sudden opening movement.

It is an object of this invention to provide an improved carburetor of the type described wherein a weighted air valve takes the place of the usual spring controlled valve and also acts as an air pump to inject additional fuel for acceleration purposes upon a sudden opening movement of the valve. The weighted type of air valve itself has important advantages over the spring urged valve as the spring force increases as it is compressed during the opening movement of the ve and therefore increases the suction required to further open the valve, thus requiring some added complications in the fuelfeeding system to compensate for the unbalanced valve opening. With the weighted type of valve on the other hand the resistance or weight is constant so that the s tion differential-required to further move the valve is substantially the same at any position so that at full capacities the suction drop due to the air valve will be much less than with a spring pressed air valve, thus materially increasing the inflow of air and increasing the volumetric efiiciency of the engine for a given carburetor size.

It is also an object of this invention to provide an improved accelerating pump wherein a dash-pot associated with the air valve compresses air above the fuel to cause an extra supply thereof to be sprayed through the normal fuel nozzles.

Other and further important objects of this invention will be apparent from the disclosures in the specification and the accompanying drawings.

This invention (in a preferred form) is illustrated in the drawings and hereinafte more full described.

On the rawings:

Figure 1 is a central vertical section through a carburetor embodying one form of'this invention;

Figure 2 is a section on the line 11-11 of Figure 1 showing the accelerating well.

Figure 3 is a section artl in elevation taken on the line IH II l of Figure 4.

Figure 1 is a central vertical section t rough a carburetor embodying a modified orm of the invention wherein the accelerating pum increases the air pressure in the float cham er.

As shown on the drawings:

All four figures embody the same by e of structure except for the; means of supplying excess fuel for acceleration. so that a general description of the carburetor shown will first be given, the same reference numerals being applied to the subject matter common. to both forms of the invention.

A fuel chamber 10 with the usual cover 11 and float mechanism 12 is provided with an outstanding shelf 13 apertured for the necessary fuel supply passages to the fuel nozzles. A downwardly inclined passage 14 from the chamber 11 leads to a larger upwardly inclined passage 15 in Figures 1 and 2, aball 16 in the latter passage acting as a check or non-return valve acting against a seat 17 in the passage, the angle of this seat being so chosen that the opening movement of the ball will be substantially horizontal in order that the ball may move as freely as possible in both directions. In Figs. 3 and 4 the ball is omitted and the passage 15 leads directly from the fuel chamber. In both forms the passage 15 leads to a longitudinal passage 18 communicating with a primary nozzle 19, an intermediate speed nozzle 20 and a high speed nozzle 21. This primary nozzle feeds into a primary air passage 22 formed between the shelf 13 and the carburetor body 23 proper, which is substantially an open ended shell defining a passage 24 therethrough and having amounting flange 25 and throttle valve 26 at one end and an air inlet pipe 26, with a choke valve 27 therein, attached to the other end. The primary air passage 22 opens into the air inlet pipe 26 adjacent the passage 24 and is also connected to the passage 24 by a primary venturi .28 aligned with the rimary fuel nozzle, this primary air passage orming a bypass around a gravity or weighted the stem to have to permit the weH to refill after emptying, an n cross passage 46 which passage when in the position shown in the 1 figures. This flap'valve 30 islifted by the suction in the carburetor when the throttle valve 26 is opened beyond the ca acity of the primary venturi, and the air owing past the lower edges of the valve 30, when partly open, brings the intermediate nozzle 20 into action. When the flap valve approaches its maximum opening the strongsuction brings the high speednozzle 21 into action.

A dashpot chamber 32 is mounted above the carburetor body and opens thereinto, containing a,piston 33 which is loosely held on the ball end 34 of a link 35 pivoted to the flap valve 30. The piston is provided with a hollow upstanding stem 36- which slides in a closed end pilot chamber 37 forming a reduced continuation of the dashpot'chamber. The stem 36 is closed at the top by a plug 38 having a restricted air passage which causes a dashpot action in the pilot chamber. The b passage 39 opening into the ball recess 40 together with a cross passage 41 opening into the dashpot chamber. loosely held in the recess 40 by a ring 42 having cut-out portions 43, shown in Fig. 2, these cut-out passages 43 forming an air inlet to and around the ball end when the latter is resting against the ring 42 andis therefore out of sealing contact with the recess. 40 around the inlet to the passage 39. In this position air is enabled to enter the passage 39 and to refill the dashpot chamber through the cross passage 41 while the weight of the flap valve acting through the link 35 pulls the piston downwards. v

Av non-return ball check valve 44 is provided in the delivery outlet 45 from the dashpot chamber 32 in both forms of the invention. Likewise both forms apply the air pressure, generated on the upstroke of the piston, to the fuel in the passage 15 supplying the nozzles, thus spraying additional fuel therefrom to meet the acceleration requirements whenever the throttle is opened suddenly enough to cause sufiicient motion of the flap valve and the piston actuated thereby. The two illustrated methods of applying this pressure to the fuel require the only distinctions in structure between the two forms.

In Figs. 1 and 2 the outlet 45 opens into a in turn opens into a vertical passage 47 having a standpipe 48 forming an accelerating well which is supplied with fuel from the passage 15. In order air bleed 49 is provided in the assage 46. In the operation of this form of t e invention an upward movement of the piston delivers air under pressure to" the passa e 47 where the increased pressure is a pli in the passage 15 and t e nozzles, this presottom of the stem also-has a The ball end 34 is trolled by the to all the fuel.

sure acting to roll the ball 16 against its seat 17, preventing back flow to the float chamber 0. The accelerating well 48 supplies the re quired additional fuel, and by varyingthe size of the standpipe the var ing require.- nents of different engines can taken care 0 In the modification outlet 45 from the dashpot chamber 32 is connected by a nipple 50 and tubing 51 to the cover 11 of the fuel chamber 10 so that.

the air pressure generated by the dashpot p1ston acts on the surfaceof the fuel to sup 1 more fuel to the several nozzles. In effect t 1s modification produces the same result, as the necessary small vent 52 in the fuel chamber dissipates the excess pressure in a short time so that an excess of fuel is not injected at a single movement of the dashpot piston.

It will thus be seen that I have provided an improved carburetor wherein a weighted ty e air valve actuates a dashpot piston which in turn increases the pressure on the fuel supplying the fuel nozzles thus not only acting as an accelerator pump but also as a check on the fluttering of the weighted air valve.

I am aware that many changes may be made and numerous details of construction may be varied through a wide range without departing from the principles of this invention, and I, therefore, do not purpose limiting the patent ranted hereon otherwise than necessitated by the prior art.

I claim as my invention:

A carburetor of the class described com- A connection fromsaid dash pot to the nozzle fuel supply.

A carburetor of the class described comprising a passaged body, fuel'nozzlesin said of Figs. 3 and 4 the body opening into the passage therein, means for supplying fuel to said nozzles, a flap valve pivoted in said giassage and adapted to var the area thereo a dashpot piston connected tosaid valve,

movement of said flap valve, 21 dashpot for said piston, an accelerating well associated with the fuel supply means for said nozzles, a non-return valve in said fuel supply means and from said dashpot to the acceleratin well.

A carburetor of the class descri ed compr sing a passaged body, fuel nozzles in said ody opening into the passage therein, means for suplplying fuel to said nozzles, a flap valve pivote in said assage and adapted to vary the area thereo a dashpot piston connected thereto, an air valve in said piston controlled an air valve in said piston cona pneumatic connection prisinga body passaged for primary and for supplying fuel thereto,

main air supphes, fuel nozzles adapted to supply fuel to both said passages, a common fuel supply passage for said nozzles a flap valve in said main air assage, and a pneumatic dashpot associate with said flap valve adapted ,to temporarily increase thefpressure of the fuel in said common fuel supply pas sage for acceleration. 5. A carburetor of the class described comprising a body passaged for primary and main air supplies, fuel nozzles adapted to supply fuel to both said passages, a common fuel supply passage for said nozzles, means a check. valve in saidmeans, afia valve in said main air passage, and a pneumatic dashpot associated with said,fiap' valve adapted to temporarily increase the pressure of the fuel in said common fuel supply passage for acceleration.

6. A carburetor of the class described comprising a body passaged for primary and main air supplies, fuel nozzles adapted to supply fuel to both said passages, a common fuel supply passage for said nozzles, an accelcratingwellcommunicatingwithsaidpassage, a flap valve in said main air passage, and pneumatic pumping means operatively connected to said flap valve adapted to increase the pressure above the fuel in said accelerating well and spray the same from said nozzles. 7. A carburetor of the class described comprising a body passaged for primary and main air supplies, fuel nozzles adapted to supply fuel to both said passages, a common fuel supply passage for said nozzles, an accelerating well communicating with said passage, a non-return valve in said passage, a flap valve in said main air passage, and pneumatic pumping means operatively connected to said flap valve adapted to increase the pressure above the fuel in said accelerating well and spray the same from said nozzles.

8. A carburetor of the class described comprising a passaged body, fuel nozzles in said body opening into the passage therein, asuc-' tion responsive air valve controlling the passage in said body, a dashpot, a piston therein operatively connected to the air valve, and a pneumatic connection from said dashpot to the nozzles, whereby the flow of fuel'from tion responsive air valve controlling the passage in said body, a dashpot, a piston therein operatively connected to the air valve, a pneumatic connection from said dashpot to the nozzles, whereby the flow of fuel from said nozzles will be increased by a movement of the dashpot, and a non-return valve in said pneumatic connection to retard the action of the dashpot to one direction of movement.

10. carburetor of the class described comprising a passaged body, a fuel nozzle insaid body opening into the passage therein,

a suction responsive air valve controlling the passage in said body, a dashpot, a piston therein operatively connected to the air valve, and a pneumatic connection from said dashpot to'the nozzle, whereby the flow of fuel from said nozzle will be increased by a move ment of the dashpot. I In testimony whereof I have hereunto subscribed my name at Flint, Genesee county,

Michigan. 7

CHARLES H. KIRBY.

said nozzles will be increasedby a movement prising a passaged body, fuel nozzles in said body opening into the passage therein, a suc- 

